Electric arc lamp



(No Model.) 3 Sheets-Sheet 1.

W. J. DAVY.

ELECTRIC ARC LAMP.

No. 580,256. Patented Apr. 6, 1897.

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(No Model.) 3 Sheets-Sheet 2.

W. J. DAVY. ELECTRIC ARC LAMP.

No. 580,256. Patented Apr. 6, 1897.

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(No Model.) 3 Sheets-Sheet 3.

W. J. DAVY.

ELECTRIC ARC LAMP.

No. 580.256. Patented Apr. 6, 1897.

UNITED STATES PATENT OFFICE.

IVILLIAM J. DAVY, OF LONDON, ENGLAND, ASSIGNOR TO THE DAVY ELEC- TRICAL CONSTRUCTION COMPANY, LIMITED, OF SAME PLACE.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent N 0. 580,256, dated April 6, 1897.

A plicati fi1 d December 9, 1895, Serial No. 571,515. (No model.)

To aZZ whom it may concern.-

Be it known that I, VVILLIAM J AMES Davy, a subject of the Queen of Great Britain and Ireland, and a resident of Holloway, London, England, have invented certain new and useful Improvements in Electric-Arc Lamps; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to to which it appertains to make and use the same.

This invention for improvements in electric-arc lamps relates more especially to lamps in which the positive and negative carbon holders are connected together by a chain or I 5 cord passing over a pulley and in which the upper-carbon holder tends to descend by gravity and thus at the same time to draw up the lower-carbon holder, so as to bring the two carbons into contact, but is also applicable to other lamps; and it consists of a friction-surface geared to and moving with the carbonholder, a carrier adapted to be rotated round the axis of the friction-surface, a brake-shoe pivoted on the carrier in close proximity to the friction-surface, a lever mounted on the carrier, an articulated or jointed connection between the brake-shoe and the lever, whose effective length is altered 011 operating the lever to bring the brake-shoe into contact 0 with the friction-surface when the continued operation of the lever rotates the lever bodily with its fulcrum and the brake-shoe about the axis of the said frictionsurface, and a means for determining the position of the 3 5 brake-lever according to the resistance of the are; also of an automatic cutout, which will out in again if the lamp should right itself, and also of a spring carbon-holder that can adjust itself to bear over a length of the carbon. Preferably the pulley makes one complete revolution only to totally consume the carbons.

In the accompanying sheet of illustrative drawings, Figure l is a side sectional elevation of the upper part of a duplex-arc lamp constructed according to this invention. Fig. 2 is a front elevation with the covers removed, and Figs. 3, 4:, and 5 are sectional plans. Figs. 6, '7, and 8 are detail views of the brake device. Fig. 9 shows the gripping device operated by a different solenoid arrangement,

and Figs. 10, 11, and 12 modifications of the gripping device. Figs. 13, 14, and 15 are detail views of a cut-out, and Figs. 16, 17, 1S, and 19 are detail views of two modified eonstructions of carbon-holder.

Each upper-carbon traveler a is guided on two parallel rods l), and each lower-carbon holder 0 is attached to a tail-rod d, secured to a traveler e, guided on two parallel rods f. The two travelers a and c for each pair of carbons are connected together by cords a c, passing over and secured to the pulley 7b. The pulleys 7b are mounted loosely on the same spindle 2', fixed in the pillar Z, secured to the base-disk m. The rods 7) are fixed by means of the distance-plates b and the rods f by the saddle-shaped distance-plates f, crossing over the plates Z). The periphery of each cord-pulley 7L is of 'ulcanite or similar insulating material Iitted on a flanged metallic pulley 7t, and the current is conveyed to the carbons through the cords.

Each metallic pulley 70 is hollow and a split ring 0, forming thecarrier and made in two parts hinged at o, tits loosely within the pulley 7L and carries the projections 0 forming the brake-blocks. A brake-lever n is pivoted to one free end of the split ring 0, and a pin it on the lever bears on the other free end of the split ring. The downward motion of the lever is limited by the stop n Fig. 1. If the end of the lever n be pulled upward, it first rotates slightly on its pivot and the pin a acts on the end of the ring to expand it and cause the blocks at o to grip within the pulley 7t. The pulley-ring and lever are then rotated bodily round the axis of the pulley and separate the carbons, the lever being raised off its stop.

The brake-levers a of both sets of carbons are operated by links p from the same arm of a solenoid-lever p, pivoted on a horizontal axis p mounted in the pillar Z. The solenoidcore 5 of the solenoid s is attached to the other arm of the lever, so that the weight of the core tends to raise the links 1) and levers 'n to separate the carbons. The solenoid is arranged as a shunt to the are.

Normally the weight of the solenoid-core raises the links 1) and the brake-levers 11, causing the pulleys 7L to be first gripped and then rotated to separate the carbons. On passing the current to the lamp the whole current tends to pass through the solenoid s,

which draws its core 3 upward. The links p and brake-levers n then descend and the levers a come successively against their stops and withdraw the brake-blocks from the friction-surfaces and allow the carbons to feed together. The greater portion of the current then passes through the carbons and the solenoid-eore .9 falls downward, again raising the links 1) and lifting the brake-levers v2 successively from off their stops and separating the carbons, the pair last separated striking the are. The solenoid then takes up an intermediate position according to the resistance of the are with one lever a raised oi't' its stop and the corresponding carbons separated and the other lever a just resting on its stop and withdrawing the brake-shoes sufli ciently to allow the pulley of the first pair of carbons to rotate slowly and regularly to feed the carbons together as they consume away. Then the first pair of carbons is consumed, the lowercarbon-holder tail-rod comes against a stop and prevents them feeding farther together and the second lever n comes against its stop and brings the second pair of carbons into operation. A dash-pot r serves to steady the motion.

In the modification shown in Fi 9 the lever 1) is connected to the cores 8' s of the shunt and series solenoids s s, and in this case the lever a normally rests on its stop with the carbons in contact. On the current passing to the lamp the series solenoid s" draws in its core and strikes the are and the shunt-solenoid 3 acts in the usual way to steady and regulate the length of the are. It will be seen that in the first-described arrangement the weight of the core .9 performs the same function as the series solenoid and its core in the last arrangement.

It will be readily understood that the split ring may be replaced by any other suitable carrier adapted to rotate round the axis of the pulley or that the brake device may be operated by any other arrangement of solenoids.

In the modification of brake shown in Fig. 10 the lower brake-block is replaced by a triotion-roller 0 so as to reduce the friction of the brakes weight and allowa more delicate feed.

In the modification of brake shown in Figs. 11 and 12 two brake-levers I, each carrying a brake-shoe If in close proximity to the internal surface of the pulley h, are mounted loosely on a pivot 11, carried near the opposite internal surface of the pulley by a carrierlever n mounted loosely on the spindle t'. In Fig. 11 the brake-levers t are separated to cause the shoes 6 to grip the internal surface of the pulley 7r by means of the elliptical cam w, pivoted to the end of the carrier-lever n and rigid with an arm 10, operated by the link 2), Fig. 1.

In Figs. 7 and S the elliptical cam is replaced by the crank-arms 20 and links 20 The brake mechanism is also applicable to lamps in which the carbons are fed together or one carbon is fed against the other by toothed gearing or the like, the friction-pulley being connected by gearing to the lamp mechanism, so that it is rotated as the carbonholders are traversed.

The shunt-lamps will work in a series circuit with different currents. Thus, say, d uring the beginning of the evening a twelveampere current can be sent through the main and later on an eight-ampere current, so that the light of a series circuit can. be perfectly regulated from the electric generator or by resistances.

\Vhen workin a number of lamps governed by a shunt-solenoid and weight in a series circuit by a series electric generator, in order to excite the generator a resistance equal to the working resistance of the circuit is inserted across the terminals of the machine, and when the generator has attained the proper electromotive force the current is shunted across to the lamp-circuit either by hand or automatically.

The cut-outand cut-in consists of a contactpiece adapted. to make contact to shortcircuit the lamp and its own operatingmeclr anism when the are becomes abnormally long and a latch-lever carrying a contactpiece adapted, when the lamp has been short-circuited, as above, to fall under and make contact with the first contact-piece to continue the short-cireuiting until a current is again established through the lamp.

Referring more especially to Figs. 13, ll, and 15, the lever 17, operated by the shuntsolenoid s, Fig. 1, carries a contact-piece p and fixed above this contact-piece is a contactpiece 19 A latch-leverw, carryin a contactpiece so, is pivoted to the frame of the mag not w so that it tends to fall under the contact-piece p when the contact-piecep is in its raised position. The lever x is attached to the armature 5c of the magnetav", which is connected in series with the carbons. The contact-piece is connected through the frame of the magnet to one terminal of the lamp, and the contact-piece p" is connected to the same terminal. The contact-pieee p is connected through a resistance 0;" to the other terminal of the lamp.

The action is as follows: The shunt-solenoid s, when the are becomes abnormally long, raises the weighted contact-piece 1p against the fixed contact-piece p and short eircuits the lamp through the resistance The se ries magnet then allows the latch-lever w to drop under the weighted contact-piece 21 and make contact therewith before the said eontactpiece falls owing to the shunt-solenoid beingshort-eircuited. The lever pis then in such a position that the brake has released its hold on the friction-pulley, so that the carbons are free to come together.

If the our rent through the carbons be again established by forcing the carbons into contact, shaking the lamp, or otherwise, the series magnet 00 attracts the latch-lever 00, opening the short circuit, and the lever 13 is again free.

The spring carbon-holder shown in Figs. 16 and 17 consists of a split socket 1 2, the two portions of the socket being connected together at their ends by the springs 3. The two parts thus tend to press on the carbons over their Whole length.

In the modification shown in Figs. 18 and 19 a fiat spring 4: is rigidly attached to the part socket 1 and loosely to the part socket 2, so that one side of the socketis free to pivot to a slight extent in the direction of its length.

What I claim, and desire to secure by Letters Patent, is

1. In electric-arc lamps the friction device for controlling the motion of the carbon holder consisting of a frictionssurface geared to and moving with the carbon-holder, a car rier adapted to be rotated round the axis of the friction-surface, a brake-shoe pivoted on the carrier in close proximity to the frictionsurface, a lever mounted on the carrier, an articulated or jointed connection between the brake shoe and the lever whose effective length is altered on operating the lever to bring the brake into contact With the frictionsurface when the continued operation of the lever rotates the lever bodily with its f ulcrnm and the brake-shoe about the axis of the said friction-surface, and a means for determining the position of the brake-lever according to the resistance of the are.

2. In electric-arc lamps the friction device for controlling the motion of the carbonholder consisting of a friction-surface geared to and moving with the carbon-holder, a split ring mounted in close proximity to the said surface, a cam-lever pivoted to one end of the split ring and adapted at the first part of its motion to act on the other end to cause the ring to grip the surface and thus lock the parts together so that in its further motion it moves bodily round with the split ring and friction-surface to separate the carbons, and a means for operating the cam-lever according to the resistance of the are.

3. In electric-arc lamps the friction device for controlling the motion of the carbonholder consisting of a friction-surface geared to and moving with the carbon-holder, a

brake-lever with brake-shoe in close proximity to the friction-surface and pivoted eccentrically to the friction-surface, a carrier-lever pivoted concentrically to the friction-surface and carrying the brake-lever pivot a controlling-lever mounted on the carrier-lever and adapted to operate the brake-lever, and a means for determining the position of the controlling-lever according to the resistance of the are.

4. I11 electric-arc lamps the friction device for controlling the motion of the carbonholder consisting of a friction-surface geared to and moving with the carbon-holder, a carrier adapted to be rotated round the axis of the friction-surface, brake-shoes mounted on the carrier and adapted to act in opposite directions on the said surface to grip it and then rotate with it, a lever-cam adapted to approach or recede the brake-shoes in respect to one another to cause them to grip on. the surface, and a means foractuating thelevercam according to the resistance of the are.

5. A cut-out for an arc-lamp consisting of a contact-piece adapted to make contact with a second contact-piece to short-circuit the lamp and its own operating mechanism when the arc becomes abnormally long, and alatchlever carrying a third contact-piece adapted when the lamp has been short-circuited as above to fall under and make contact with the first contact-piece to continue the shortcircuitin g until a current is again established through the lamp.

6. A cut-out for an arc-lamp consisting of a weighted contact'piece, a shunt solenoid and core adapted to raise the contact-piece, a second contact-piece fixed in the path of the moving contact-piece, a series magnet and armature, a latch-lever connected to the armature and forming a third contact-piece tending to fall under and make contact with the moving contact-piece and hold it in its raised position; the first contact-piece being connected through a resistance to one terminal of the lamp and the other two to the other terminal.

In testimony whereof I have affixed my sig nature in presence of two witnesses.

WILLIAM J. DAVY.

'Witnesses:

ALBERT Jonns, GEORGE CAMPBELL, 

